On 18 September, the World Meteorological Organization (WMO) published its fourth edition of the annual “State of Global Water Resources Report”. It contains a quantitative assessment of various components of the global water cycle and a comparative analysis of data from the past year with data from a reference period aimed at highlighting changes in the water cycle.
Three global data centres based in Koblenz make significant contributions to the report. ICWRGC and BfG, via the ISMN, have been involved in preparing the report since the 2022 edition, the second of its kind. BfG’s Global Runoff Data Centre (GRDC) even started contributing as early as 2021. The latest report now also includes global water quality data provided by the GEMS/Water Data Centre which is hosted by ICWRGC/BfG.
This year’s edition revealed the following key findings:
- 2024 was the hottest year in the 175-year observational record, with the mean temperature reaching 1.55°C above the baseline.
- River discharge in 2024 exhibited deviations from normal conditions in approximately 60% of global catchment areas. Above-normal discharge mainly occurred in European, Asian and West African basins, while South American and southern African basins recorded below-normal discharge conditions.
- Considerable soil moisture deficits were observed across large parts of South America, Africa and the Mediterranean basin during the reporting year. In contrast, soil moisture in Central Europe and the Horn of Africa remained above normal.
- 2024 was a year marked by a number of extreme events which were a result of excess water, with European, African and Asian regions being particularly hard hit.
- In more than 60% of global catchment areas, the validation of modelled data against in situ data showed good agreement, which was also true when comparing the results obtained from different modelling systems.
- There is an urgent need for improved monitoring and data sharing, because we cannot manage what we do not measure. Without data, we risk flying blind.
While the overall number of global measurements is in decline, there are encouraging signs too. The number of observed data points for river discharge measurements increased significantly: from 14 stations in 7 countries for the first report to 2,777 stations in 41 countries for the 2024 edition. Parameters particularly affected by the scarcity of in situ data were soil moisture (ISMN) and water quality (GWDC). In both cases, data coverage did not meet the report’s requirements, but an in-depth discussion is included in the annex.
A detailed summary of the report can be found in a WMO StoryMap, and the full report is available for download here.
ICWRGC and BfG will continue to contribute significantly to the compilation of future “State of Global Water Resources” reports via their data centres. They remain committed to promoting international sharing of water data in order to establish river discharge, soil moisture and water quality data as integral parts of the report.
The report will also form a major basis of discussion for the “Water for Planet” interactive dialogue at the UN 2026 Water Conference.
